a) Field of the Invention
The present invention relates to a vapor phase process technology, and more particularly to a technology of a vapor phase process for processing semiconductor wafer surface by supplying a process gas to the surface.
b) Description of the Related Art
As semiconductor devices are becoming fine, the number of manufacturing processes has increased and the processes have become complicated. An increase of manufacturing steps is one off the main reasons which lowers a yield off semiconductor devices. An increase of manufacturing steps also increases the number of manufacturing apparatuses and raises a manufacturing cost. It has been desired therefore to lower the cost by sharing manufacturing processes and apparatuses.
Multi chambers of an apparatus have progressed much so as to satisfy the demands for sharing manufacturing processes and apparatuses, and the number of process steps to be performed by the same apparatus has increased. However, a time required for replacing a gas in a reaction process chamber of a chemical vapor deposition system or the Like with an inert atmosphere has not been shortened satisfactorily. Even in the same system, a wafer is transported from one chamber to another so that the problem of particle attachment occurs.
A natural oxide film formed on a processed wafer surface before the wafer is passed to the next process has recently given rise to new trouble. It is an urgent issue to solve these problems because semiconductor devices are expected to become finer and finer, and the natural oxide will be no more of negligible thickness.